phase: 178_split_thinking_levels

## Phase 178 — final verification pass: 100% green

**Verified (all 5 tasks complete in `complete/178_split_thinking_levels/`):**
- `config.py` rename (`llm_chat_thinking_level` default `low`) + new `llm_summary_thinking_level` (default `""`); two `CATALOG` rows; `.env.example` replaced; no stale old-key references (only intentional negative pins in tests)
- Wire split: `chat_stream()` → chat level, one-shot `chat()` → summary level (absent `extra_body` when empty); per-turn line reads chat level only

**Gates:**
- `uv run pytest -k "config and thinking" -v` → 7 passed (defaults + env overrides both knobs)
- `uv run pytest` (unit + integration) → 4170 tests, exit 0; `--cov=app` → **99%** (>90% ✓)
- `uv run ruff check .` clean; `uv run pyright` clean
- `uv run pytest tests/e2e/test_split_thinking_levels.py -v --no-cov` → 3 passed in isolation
- `test_admin_settings_panel.py` + `test_admin_settings_layout.py` → 17 passed in isolation

**Completion criteria:** all 6 test/doc criteria ✅ (admin GET lists both keys, old key gone — integration + E2E pins); commit + phase-dir move = harness's job.

**Documentation:** README.md — both new env vars correctly documented in the LLM (aipi) table with defaults/wire-mapping/off-rule, defaults match `config.py`, all `.env.example` vars covered: verified consistent, no changes needed. AGENTS.md — all referenced files/commands verified to exist, no phase-178 impact (no UI code change, A4): verified consistent, no changes needed.

**Decisions:** none required — no live changes made (E2E booted its own app subprocess against the existing DB).

**Next pending phase:** none — 178 is the last phase in `todo/`.

tests/unit/test_chat_gate.py

@@ -1550,8 +1550,13 @@ def test_endpoint_log_line_records_suggested_after_summary_hits(
     seeded suggestion tier's size (``len(plan.suggested_docs)``).
     Phase 172 (A6): the line gains ``thinking=<level>`` immediately
     BEFORE ``thinking_chars=N`` — the effective (overlay-resolved)
-    ``BOR_LLM_THINKING_LEVEL``, trimmed, ``-`` when empty (the off
-    switch)."""
+    ``BOR_LLM_CHAT_THINKING_LEVEL`` (the chat level), trimmed,
+    ``-`` when empty (the off switch).
+    Phase 178 (A5): the field stays pinned to the CHAT level — the
+    level the turn actually ran at; the one-shot summary level
+    (``llm_summary_thinking_level``, a different knob) is never read
+    by the line and must not leak into the line's ``thinking=``
+    value (cross-pin + inverse off-pin below)."""
     _session, _llm = gate_env
     doc = _doc("Kubernetes Homelab Cluster", "TALOS_DOC_SENT")
     chunks = [_chunk(doc, 0.30), _chunk(doc, 0.20, is_summary=True)]
@@ -1606,7 +1611,7 @@ def test_endpoint_log_line_records_suggested_after_summary_hits(
     monkeypatch.setattr(
         chat_api,
         "get_settings",
-        lambda: Settings(_env_file=None, relevance_threshold=0.30, llm_thinking_level="high"),  # pyright: ignore[reportCallIssue]
+        lambda: Settings(_env_file=None, relevance_threshold=0.30, llm_chat_thinking_level="high"),  # pyright: ignore[reportCallIssue]
     )
     line = _last_log_line()
     assert "thinking=high thinking_chars=" in line
@@ -1615,7 +1620,7 @@ def test_endpoint_log_line_records_suggested_after_summary_hits(
     monkeypatch.setattr(
         chat_api,
         "get_settings",
-        lambda: Settings(_env_file=None, relevance_threshold=0.30, llm_thinking_level=""),  # pyright: ignore[reportCallIssue]
+        lambda: Settings(_env_file=None, relevance_threshold=0.30, llm_chat_thinking_level=""),  # pyright: ignore[reportCallIssue]
     )
     line = _last_log_line()
     assert "thinking=- thinking_chars=" in line
@@ -1625,7 +1630,42 @@ def test_endpoint_log_line_records_suggested_after_summary_hits(
     monkeypatch.setattr(
         chat_api,
         "get_settings",
-        lambda: Settings(_env_file=None, relevance_threshold=0.30, llm_thinking_level="   "),  # pyright: ignore[reportCallIssue]
+        lambda: Settings(_env_file=None, relevance_threshold=0.30, llm_chat_thinking_level="   "),  # pyright: ignore[reportCallIssue]
     )
     line = _last_log_line()
     assert "thinking=- thinking_chars=" in line
+
+    # Phase 178 (A5) cross-pin: the line is pinned to the CHAT level
+    # — with the one-shot summary level set to a DIFFERENT value,
+    # the line still shows the chat level; the summary's "high"
+    # does not appear as the line's ``thinking=`` value.
+    monkeypatch.setattr(
+        chat_api,
+        "get_settings",
+        lambda: Settings(
+            _env_file=None,  # pyright: ignore[reportCallIssue]
+            relevance_threshold=0.30,
+            llm_chat_thinking_level="low",
+            llm_summary_thinking_level="high",
+        ),
+    )
+    line = _last_log_line()
+    assert "thinking=low thinking_chars=" in line
+    assert "thinking=high" not in line
+
+    # The inverse off-pin: the chat off-switch logs ``-`` even
+    # though the one-shot summary knob is set — only the chat level
+    # (the level this turn ran at) rides the line.
+    monkeypatch.setattr(
+        chat_api,
+        "get_settings",
+        lambda: Settings(
+            _env_file=None,  # pyright: ignore[reportCallIssue]
+            relevance_threshold=0.30,
+            llm_chat_thinking_level="",
+            llm_summary_thinking_level="high",
+        ),
+    )
+    line = _last_log_line()
+    assert "thinking=- thinking_chars=" in line
+    assert "thinking=high" not in line